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Image Credit:
Pärssinen et al., Nature (2026)
LiDAR Reveals More Than 20,000 Ancient Earthworks in the Amazon
Airborne laser scanning has revealed that southwestern Amazonia may contain between 24,000 and 30,000 precolonial earthworks, far more than previously recognized. The findings suggest that the region once supported a large, organized population whose settlements and ceremonial landscapes extended across approximately 183,000 square kilometres.
The research focused on parts of the Brazilian states of Acre and Amazonas, where dense forest has hidden many archaeological structures from conventional aerial and satellite observation. Using LiDAR, a technology capable of recording ground surfaces beneath vegetation, researchers surveyed more than 4,400 kilometres of flight paths and documented 432 earthworks. Only 36 of them had been identified previously.
The newly detected features include geometric ditched enclosures, embanked structures and later mound villages. Many are associated with a precolonial society identified by the researchers as the Aquiry civilization, which began constructing monumental earthworks more than 2,500 years ago.
The structures vary considerably in size. Most geometric enclosures cover between 0.35 and 14 hectares, although the largest known example approaches 50 hectares. Some occur individually, while others form complexes containing several connected enclosures and roads.
Researchers interpret many of these earthworks as ceremonial, political and public gathering centres rather than permanently occupied or defensive settlements. Their construction required extensive labour, planning and knowledge of geometry. Maintaining such centres over many centuries also implies organized leadership and shared social and cosmological traditions.
The LiDAR survey proved considerably more effective than satellite imagery. In deforested portions of one study area, it detected approximately five times as many structures as had previously been recognized from online satellite images. Many embanked enclosures were especially difficult to identify without detailed models of the underlying terrain.
By combining the new LiDAR results with earlier archaeological surveys and satellite mapping, the study estimates that approximately two-thirds of the region’s earthworks belonged to the Aquiry period. The remaining structures include later villages and enclosures built after about AD 1000.
Radiocarbon evidence suggests that the Aquiry society reached its greatest extent between approximately AD 100 and 300. The researchers estimate that between 25 and 60 percent of its ceremonial centres may have been used during this period.
Based on the labour needed to build and maintain the earthworks, comparisons with later mound villages and ethnographic information from Indigenous communities, the study proposes that the Aquiry population may have reached between 1.25 and 3 million people. Taking into account archaeological features that LiDAR may still have missed beneath exceptionally dense vegetation, the possible figure could be even higher.
The findings challenge older portrayals of Amazonia as a sparsely inhabited environment incapable of supporting complex societies. Archaeological evidence indicates that local communities cultivated maize and squash and probably grew manioc, sweet potatoes, beans, peanuts and chilli peppers. They also managed useful tree species, including Brazil nuts and several palms.
Such activities left lasting effects on soils, forests and biodiversity. The distribution of cultivated and semi-domesticated plants around earthworks shows that the modern forest partly reflects thousands of years of human management.
Researchers describe this dispersed pattern of settlements and monumental gathering places as a possible form of low-density or forest urbanism. Rather than concentrating residents within a single large city, communities were distributed across the landscape but connected through ceremonial centres, roads, shared traditions and exchange networks.
If comparable concentrations of hidden archaeological structures are found elsewhere, estimates of the precolonial Amazonian population and the long-term human influence on the rainforest may require substantial revision.
Published on: 30-07-2026
Edited by: Abdulmnam Samakie
Source: Nature
